001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.hadoop.hdfs.server.namenode.snapshot;
019    
020    /**
021     * This is an interface used to retrieve statistic information related to
022     * snapshots
023     */
024    public interface SnapshotStats {
025    
026      /**
027       * @return The number of snapshottale directories in the system 
028       */
029      public int getNumSnapshottableDirs();
030      
031      /**
032       * @return The number of directories that have been snapshotted
033       */
034      public int getNumSnapshots();
035      
036    }